MDARD Michigan Core Pesticide Applicator Practice Exam

Which LD50 value represents a relatively non-toxic pesticide?

1. 640 mg/kg

2. 5,800 mg/kg

3. 12,840 mg/kg

4. 380 mg/kg

The correct answer is: 12,840 mg/kg

The LD50 value is a measure of the lethal dose of a substance that kills 50% of a test population, typically expressed in mg of substance per kg of body weight. The higher the LD50 value, the lower the toxicity of the pesticide. In this context, an LD50 value of 12,840 mg/kg indicates that a relatively large amount of the pesticide must be ingested or absorbed to reach a lethal dose for half of the tested organisms. This suggests that the substance is much less toxic compared to those with lower LD50 values. Therefore, it is considered to be relatively non-toxic. Comparatively, lower LD50 values, such as 640 mg/kg, 380 mg/kg, and even 5,800 mg/kg, represent higher toxicity levels where smaller doses can be harmful or lethal, indicating that these pesticides pose a greater risk to health and safety. Understanding these values is critical for the safe application and handling of pesticides, as it informs applicators about the potential hazards associated with specific products.